That's the way I've always looked at it.
The beauty of the 9200 is it can be used with any old VGA card. It can also do the 15khz stuff if you want to set it up and have a card capable of it. Otherwise, it is nice to just plug it in and go, without bothering with advanced settings.
The beauty of the arcadevga is it makes hooking up a 15khz arcade monitor a snap. Arcade monitors can be used with many standard, cheap vga cards, but it takes more time and effort to get it working. The arcadevga makes it easy.
But combining both... just seems like a waste of money to me. Using an arcadevga on a D9200 just seems like a waste of the capability of the D9200 to me. Why buy a $500 brand new monitor when a used $50-100 would do the same thing (if used with an arcadevga)?
The D9200 is the ultimate in ease of use AND flexibility... using the Arcadevga (read: not flexible, but very good at its original intended purpose) with the D9200 just doesn't add up.
That said, some people do it, and there are a few good reasons to do it, but they might not be important to you. I'm sure someone else will chime in.
Wade